1. Field
The following description relates to functionalized reduced grapheme oxide (functionalized rGO), a method of preparing the functionalized reduced grapheme oxide (functionalized rGO), graphene compositions including doped and reduced graphene oxide, and methods of preparing the graphene compositions.
2. Description of Related Art
Graphene is a crystalline allotrope of carbon with two-dimensional properties. Other allotropes of carbon include diamond, graphite, carbon nanotube, bukyball, and the like. Graphene comprises a monolayer of carbon atoms arranged within a pattern of repeating honeycomb lattice in two dimensions.
Functionalized graphene has attracted considerable attention. The fictionalization of graphene can alter the chemical, structural and electrical properties of graphene. Various graphene derivatives have been synthesized such as graphene oxide (GO), graphene, different atomic doped GO, and the like. Among the derivatives, GO is one of the most extensively studied forms of functionalized graphene. GO is easily produced by exfoliating oxidized graphite. Recently, the halogenation of graphene provides another possibility for controlling chemical functionalization of graphene as in band-gap engineering. A halogen atom, which is highly electronegative, forms a stronger bond with a carbon atom than a hydrogen atom, producing a more stable graphene derivative composition. This is the principle that enables halogen atoms to accomplish efficient doping and/or band-gap initiation of the graphene. In addition, fluorinated graphene (FG) can promote nerve-guide of stem cells and is used for application of tissue engineering. Accordingly, the synthesis of halogenated graphene is drawing much attention from chemists.
In general, F or Cl plasma, or exposure to F2 at a high temperature has been used to bond F or Cl atoms to a base surface of graphene. Fluorinated graphene can be also obtained from fluorinated graphite by an exfoliating method. However, plasma may cause damage to the graphene by ion bombardment. In addition, the use of a high temperature reaction is not desirable. Decomposition of XeF2 or photochemical decomposition of Cl2 at a certain temperature has been also used for fluorination or chlorination of graphene. An electrochemical process has also been reported with regard to preparation and properties of a single-layer graphene oxyfluoride (OFG). Currently, there are published methods using hydrogen fluoride, which is a corrosive reactant, for fluorination of graphene oxide (GO). In addition, Korean Patent Application Publication No. 10-2013-0019169 describes a method for preparing fluorinated graphene by using expanded graphite. However, an efficient, simple, environment-friendly and solution-based method for synthesis of fluorinated graphene is demanded to test the characteristic of bulk production and actual application.